Clays included in the insoluble residue from 35 limestones (biomicrosparrudites) collected from the Kope and Fairview Formations in Hamilton County, Ohio were qualitatively and quantitatively analyzed to determine possible variations which might reflect changes in source during deposition of these lithic units. Illite and chlorite-vermiculite are the only clay groups identified. Illite comprises from 75 to 99 percent of the total clay fraction and averages 95 to 93 percent with the Kope and Fairview limestones respectively. No significant change in the clay percentages within insoluble residues occur across the Kope-Fairview contact, nor is there any obvious correlation between the clay percentages and mechanical energy fluctuations which occur within these two formations. These results suggest no significant variation concerning the source(s) of these clays during Kope and Fairview sedimentation.